Question

Statement 1: Atoms of different elements can have the same mass number.
Statement 2: The atoms of each element have a characteristic number of protons in the nucleus.

• A. Both Statement 1 and Statement 2 are correct and Statement 2 is the correct explanation of Statement 1.
• B. Both Statement 1 and Statement 2 are correct and Statement 2 is not the correct explanation of Statement 1.
• C. Statement 1 is correct but Statement 2 is not correct.
• D. Statement 1 is not correct but Statement 2 is correct.
• E. Both the Statement 1 and Statement 2 are not correct.

Answer 1

Answer: (B)

Both Statement 1 and Statement 2 are correct and Statement 2 is not the correct explanation of Statement 1.

Statement 1: Atoms of different elements can have the same mass number.
Different isotopes of the same element cannot have the same mass number, but isotopes of different elements often do have the same mass number, e.g., carbon-14 (6 protons and 8 neutrons) and nitrogen-14 (7 protons and 7 neutrons) both have same mass number which is 14.
Statement 2: The atoms of each element have a characteristic number of protons in the nucleus.
Thus, in the above example, carbon-14 has 6 protons and nitrogen -14 has 7 protons.
Thus, both Statement 1 and Statement 2 are correct and Statement 2 is not the correct explanation of Statement 1.